ZrO₂-HfO₂Superlattice Ferroelectric Capacitors with Optimized Annealing to Achieve Extremely High Polarization Stability

The ferroelectric polarization stability and dielectric characteristics of ZrO2-HfO2 superlattice (SL) ferroelectric layer Metal-Ferroelectric-Metal (MFM) capacitor fabricated with various post-metal annealing (PMA) temperatures were presented. It was demonstrated that ZrO2-HfO2 SL MFM capacitors with increased post metallization PMA temperature (i.e., 600 °C) showed improved polarization stability with almost wake-up free and polarization fatigue free characteristics. In this work, we have shown that highly stable remanent polarization (2Pr@ 3MV $/$ cm) of $30 ~\mu \text{C}/$ cm2 with small variation ( $\Delta 2\text{P}_{r} \le 2 ~\mu \text{C}/$ cm2; $\Delta 2\text{P}_{r} / 2\text{P}_{r,pristine} \le9$ %) up to 1011 cycles of field cycling were exhibited by the atomic layer deposition (ALD) deposited ZrO2-HfO2 superlattice with 600 °C PMA. To our knowledge, the nearly 'wake-up'-free and fatigue-free polarization behavior up to 1011 cycles are among the best polarization stability for the hafnium zirconium oxide based MFM capacitors sustained endurance tests for more than 1010 cycles.